The average age among all the 2015 Grammy nominees in the four rock categories was roughly 46, give or take a year, depending any given band's current lineup. The oldest individual is 69 (Lemmy from Motörhead); the youngest is 25 (Taylor York of Paramore).

AC/DC ripped the lid off Sunday night's show, a high-energy opener that found singer Brian Johnson, 67, and guitarist Angus Young, 59, in top form. Many still-active rock legends took part, including 72-year-old Paul McCartney, Electric Light Orchestra, who are in their late 60s, and Prince, 56. Prince also presented the coveted Album of the Year award to Beck Hansen, who is a relative rock 'n' roll spring chicken at 44.

As always, the Grammys were peppered with plenty of promising young music stars, like Best New Artist winner Sam Smith, 22, who also won Song of the Year and Record of the Year; and Best Country Album winner 31-year-old Miranda Lambert. Performers included Beyoncé Knowles, already living legend at 33, with Katy Perry, 30, Rihanna, 26, and Ariana Grande, 21, not far behind. And music's most promising star is, of course, 25-year-old Taylor Swift, who did not need to perform to make her presence felt.

Notice anything about that list of up-and-comers? None them has ever even attempted to strap on a Les Paul and just freakin' rawk out.

It's not just a Grammy thing. The truth is, you'd be hard-pressed to name a single bona fide rock star — we're talking face-melting guitar licks, larger-than-life personality and the kind of feral, subversive song that can change your life, man — who was born after 1980.

Jack White at the MusiCares Person of The Year honoring Bob Dylan held at Los Angeles Convention Center on February 6.

Image: Michael Tran/FilmMagic

But if you think rock is dead, you've forgotten the fundamental fact that Neil Young (69) taught us: Rock and roll can never die. One need only look at this summer's music festival lineup to realize that.

And perhaps the hottest ticket of summer will be the Grateful Dead's farewell shows in Chicago over the Independence Day weekend, featuring the four surviving original members (67, 68, 71 and 74). They have invited the young whippersnapper Trey Anastasio, 50, of Phish to stand in for the late Jerry Garcia, who would be 73.

Bob Weir and Mickey Hart of the Grateful Dead at the 2015 National Association of Music Merchants show in Anaheim on January 23.

Image: Photo by Jesse Grant/Getty Images for NAMM

Even the "new" rock bands who are getting traction are on the older side: Adam Granofsky of The War on Drugs will have his 36th birthday next week, while The Black Keys were hitting their mid 30s as the two-piece was hitting its stride just a few short years ago.

In the 60s and 70s — the golden age of rock, from whence most of our now-aging stars came — you were an "older" artist at 25.

Duane Allman, who founded the Allman Brothers, was already an electric guitar god by age 19; he died at age 24, and is still considered one of the instrument's greatest players. Jimi Hendrix was 24 when he broke out. Jimmy Page was the most sought-after session guitarist in England in his early 20s; he founded Led Zeppelin when he was 24. John Lennon was 24 when the Beatles first touched down in the U.S.

The Beatles in 1964.

Image: Getty Images

Yes, rock and roll is growing old, and though its popularity has never really waned, there is no younger crop coming up to fill its ranks; it is no stretch to say the Millennial generation has utterly failed to produce even a single rock artist of any cosmic import. Yes, we have Imagine Dragons and Mumford & Sons and even Grammy-performer Hozier — but these barely qualify as "rock" acts, and when the amps get cranked up, none could hold a candle to Hendrix or Pink Floyd or Jeff Beck ... or even Foghat, for crying out loud. Not even close.

They sure can't draw the kind of audiences that their elders can. Nine of the top 15 touring acts of the past decade are veteran rockers: U2, Roger Waters (of Pink Floyd), AC/DC, Bruce Springsteen, Bon Jovi, The Eagles, The Rolling Stones, Fleetwood Mac and Metallica dominate the list that includes a handful of younger acts. And none of those young acts — One Direction, Justin Bieber and Justin Timberlake among them — even play instruments, favoring choreography, personality and spectacle over musicality.

As time marches on, more and more of these acts will make their last hurrahs, like the Allman Brothers did last year and the Dead are doing this summer. Without anyone coming up to replace them, who will feed the obviously robust appetite for good old fashioned, blues-drenched, guitar-heavy, hard-stomping rock 'n' roll, with snarling lyrics and bad intentions and no backing tracks or corporate sponsors to lean on?

The Allman Brothers at The Beacon Theatre on October 28, 2014 in New York City.

Image: Getty Images

Somewhere, in a nondescript garage or basement, there must be a group of angsty teens slogging through 1-4-5 blues progressions, struggling through learn power chords and pentatonic scales and covers of The Who and Led Zeppelin and AC/DC and the Rolling Stones, with dreams of bright lights, screaming fans, tricked-out tour buses and endless hotel rooms to trash.

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